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Re: Fast operations on floating point numbers?

Peter Barada wrote:

If flipsign is only refered to inside the(hevily executed) loop, you
could try:

double a, flip;
int flipsign;

flip = flipsign ? -1.0 : 1.0;

for (;;) {
  ...
  a *= flip;
  ...
}

And get rid of the conditional... 

Unfortunately this does not work in all places where I have this
problem. But even where I can use it, there is still a
full floating-point multiplication where the simple XORing of
a single bit should do. But maybe the cost of both operations
is not so different on today's CPUs; I don't know.

Thanks,
  Martin


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